1. Field of the Invention
The present invention relates to a composition for forming a film.
2. Description of the Related Art
Cellulose ethers having low polymerization degrees have been widely applied to pharmaceutical and food fields. Of the cellulose ethers, hypromellose (also known as hydroxypropyl methyl cellulose; hereinafter also called “HPMC”) has excellent solubility in water and is dried to form a tough film. The formed film has high transparency and excellent gas barrier and moisture barrier properties, and thus the HPMC is widely applied to the film coating agent for tablets and granules. In addition, the film has excellent film properties, and thus has been used as a pharmaceutical film. As compared with gelatin that has been commonly used as the base material of capsules, the HPMC has no possibility of mad cow disease, is made from plants, and gives high capsule strength even at low water content. Hence, the HPMC is being widely used as the base material of hard capsules.
JP 3-279325A discloses that HPMC, a gelling agent and a gelling adjuvant are dispersed in hot water at 70° C. to obtain a hard capsule preparation liquid containing the HPMC as the base material; then the liquid is adjusted to 50 to 52° C., which is the temperature at which a pin for forming a capsule is immersed (hereinafter also called “immersion temperature”); and a hard capsule having low water content is produced. JP 3-279325A does not disclose a step of cooling the liquid to 35° C. or less before immersion to completely dissolve HPMC. JP 2000-136126A discloses that an HPMC dispersion having the HPMC dispersed in hot water is once cooled to 35° C. or less for completely dissolving the HPMC to obtain a capsule preparation liquid; then the capsule preparation liquid is adjusted to 35 to 50° C., which is lower than the temperature at which HPMC thermally gelates to exhibit rapid viscosity increase of the capsule preparation liquid, so that the viscosity increase of the capsule preparation liquid is suppressed; and uniform hard capsules are produced without strict control of the immersion temperature.